Charles e



(No Model.)

0. E. SCRIBNER. APPARATUS FOR TELEPHONE SWITGHBOARDS.

No. 543,902. v Patented Aug. 6, 1895.

NITED STATES PATENT OFFICE.

CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

APPARATUS FOR TELEPHONE-SWITCHBOARDS.

SPECIFICATION forming part of Letters Patent No. 543,902, dated August 6, 1895. Application filed December 8, 1894:. Serial No: 531301. (No model.)

To all whom it may concern: It has been found, however, that an operator Be it known that 1, CHARLES E. SORIBNER, in attendance upon a large number of suba citizen of the United States, residing at scribers finds it convenient to insert the first Chicago, in the county of Cook and State of or answering plugs of several pairs into the .5 Illinois, have invented acertain new and usespring-jacks of different subscribers who fulImprovementin Apparatus forTelephonehave signaled the exchange as rapidly as Switchboards, (Case No. 369,) of which the possible and to receive their orders and comfollowing is a full, clear; concise, and exact plete the desired connections successively description, reference being had to the acthereafter. This requirement prohibits the 60 1o companying drawings, forming a part of this connection of the telephone with a plug-cirspecification. cuit simultaneously with the insertion of the My invention relates to switchboards of answering-plug into a spring-jack and netelephon-exchange systems, particularly to cessitates such connection at a later stage in the mechanism controlling the connection of the process of establishing connection. 65

. :5 the operators telephone with the circuits of In my invention I provide a switch which the plugs employed for uniting different teleis actuated by the withdrawal of the final or phone lines at the switchboards. Its object test-plug from its normal resting socket or is to perform the connection and disconnecseat and acts to connect the telephone with tion of the telephone with the plug-circuit the plug-circuitand an electromagnetic switch 70 2o automatically at suitable stages in the proor relay, which is operated by the insertion cess of making connection between lines. of the same plug into a spring-jack to discon- In the telephone switchboards ordinarily meet the telephone. In general,then,the opemployed each line, as is well known, termieration of my'system is as follows: The oper mates in a spring-jack or connection socket ator having received a call-signal, inserts the 75 on the switchboard, and suitable plugs adaptanswering-plug of a pair into the spring-jack ed to fit the sockets are provided for making of the calling subscriber. She then raises electrical connection with them, the plugs bethe connecting-plug from its socket, whereby ing united in pairs by flexible conductors. her telephone becomes connected with the Each pair of plugs has hithertobeen provided plug-circuit, and, finally having learned the 8::

0 with a switch-key, by which the operator number of the line with which connection is might connect her telephone set with the cordesired, she inserts the connecting-plug into responding plug-circuit, to permit of comthe spring-jack ofthat line. By this final munication with asubscriber in whose springact her telephone is automatically severed jack one of the plugs was inserted, this confrom the plug-circuit. 85

nection being ordinarily necessary, however, In practice I have found it desirable to emonly after the insertion of a plug in the springploy a relay or electromagnetic switchfor dejack of a subscriber making a call, for the termining the connection of the telephone purpose of ascertaining with what line conwith the plug-circuit, the operation of the renection was desired. It is of course neceslay itself being controlled by the plug-seat 9o sary for the operator to remove her telephone switch and by other switchcontacts and cirfrom the circuit after the connection has been cuit connections brought into play in the comcompleted. It has heretofore been proposed pletion of the connection by the insertion of to render this connection and disconnection the connecting-plug into the spring-jack. of the telephone with the plug-circuit auto- The relay isincluded,together with a battery, 5

matic by means of a relay and circuit conin a local circuit, which is divided into two nections, such that the relay should be actparallel branches, one of which is controlled uated to connect the telephone upon the iuby the plug-seat switchthe switch being arsertion of the first plug of a pair into a ranged to close the circuit while the plug is spring-jack in answering a call and to disin its socketand the other of which is contoo 0 connect the telephone upon the insertion of trolled by co-operating contact-surfacesin the the other plug in completing the connection. spring-jacks and the connecting-plug respectively, which complete the circuit when the plug is inserted into any spring-jack.' The relay is constructed to disconnect the telephone when its magnet is excited. In a particularly satisfactory arrangement of the devices the relay does not connect the telephone directly with the plug-circuit, but with one helix of a repeating-coil, whose other helix is permanently bridged across the cord-circuit. This avoids all common connections between different plug-circuits, while permitting the use of but a single pair of switch-contacts on the relay. In the invention as thus organized the magnet of the relay is excited as long as the connecting-plug rests in its socket, the local circuit being completed through the plug-seat switch and the circuit between the repeating-coil and the telephone being thus interrupted. When the plug is lifted from its socket the previously-existing local circuit is broken and the telephone is brought into connection with the repeating-coil. Vhen the plug is finally inserted into a spring-jack to complete a connection the other branch of the local circuit is closed through the contact-piece of the plug and the co-operating contact-surface of thespring-jack into which it is inserted, and the relaynnagnet is again excited.

My invention is illustrated in the accompanying drawing. Two sub-stations are shown connected by lines with a telephone-switchboard, which is equipped with a pair of connecting-plugs to which my invention is applied.

The apparatus of the substations A and B is of the usual type. It may comprise a telephone a and transmitter a, a bell a a generator a of signaling-current, and an automatic telephone-switch a for switching the telephonic apparatus and the signaling appliances alternately into connection with the line. The station A, for example, is connected by line-wires 1 2 with two spring-jacks c and c, which may be assumed to be located upon two different sections 01 and d of a multiple switchboard. The conductors 1 and 2 of the line are united through the main or line coil of a self-restoring annunciator e, which is located at section d of the switchboard. Each of the spring-jacks comprises, in addition to the line-contacts f and f, a pair of local contact-pieces f and f The springs f are connected together by a conductor 3 and through a battery 9 to earth. Springsf are united by another conductor 4, which is also grounded, and which includes the restoring-magnet e of the line-annunciator. In addition to its contact-pieces each springjack has a test-ringf which is in electrical connection with the springf The arrangement of the circuits and apparatus of the line to station E is in all respects the same, the line-annunciator e being located at section cl of the switchboard, however. But one pair of conn ecting-plugs h h is shown. Each plug comprises a spherical conducting-tip i,

which is adapted to enter between the springs f andf and to cross them together, a short sleeve 1" in position to register with the spring f, and a longer sleeve 2' adapted to make connection with the thimblefof the springjack. The sleeves t of the two plugs are united by conductor 5 and the sleeves t by conductor 6. These conductors include the switch-contacts of the cailing-keyle, which is adapted, when its plunger is depressed, to loop a generator Z of a signaling-current into circuit with the connectingplug it. The primary helix m of a repeating-coil m is connected in a permanent bridge-wire between the conductors 5 and 6. A clearingout signal it is also connected permanently in a bridge between conductors 5 and 6.

The tip iof plug 71, has no circuit connection. The tip 1' of plug 7t, however, forms the terminal of a conductor 7, which is grounded through a relay 0. The switch-contacts o o of this relay control a local circuit 8, which includes the secondary heliit of the repeating-coil m, the operators telephone p, and a battery q. The portion of this circuit which includes the telephone and the battery may be common to all the plug-circuits belonging to one operator, the contact-levers o of the relays of the dilterent plug-circuits being connected together and to one terminal of the telephone and the other terminal of the telephone being connected with the secondary helices of the different repeatingcoils. Each connectingplug it rests normally in a socket or seat which is provided with a plug seat switch, comprising a spring a", which is adapted to be forced aside by the insertion of a plug in its socket, and an anvil 7*, against which this spring is pressed. The switch-contacts r 7' control a branch 9 from conductor 7 through thebattery g to earth. The relay 0 is thusin a local circuit 7, which is divided into two parallel branches, one of which is through the contact-points r r" of the plugseat switch and the other, when the plug 7t is insertcdintoa spring-jack, through the tip 1' of plug 7i and the spring f of the springack.

To trace the operation of the system, let it be assumed that subscriber at station A wishes to communicate with subscriber at station 1- The first or call-initiating subscriber, by retating his signaling-generator a operates the annunciator e of his line at the central station. The attendant at the switchboard (1, upon which this annunciator is located, perceiving the signal, inserts one plug 7L of a pair into the springjack c of the corresponding line. If the signal be one of a number of callsignals occurring at the same time, the oper ator may insert answering-plugs of different pairs of cords into the springjacks of all the different lines calling. Presently she raises the plug 7t from its socket, thus permitting the plug-seat switch 0 to open thelocal circuit through relay 0, thus effectin g the completion of the circuit 8, including her telephone and IIO the secondary helix of repeating-coil m. Her apparatus is thusbrought into position to permit of communication with the subscriber signaling from station A. Having learned his order, she proceeds to test the line called for namely, that of station Bby applying the tip 1' of plug it to the test-ring f of spring-jack c of that line upon her section of the multiple switchboard. It will be understood that if no connection alreadyexists with any spring-j ack of this line a circuit is formed through the relay from tip '5 to test-ring f thence through conductor 4, and restoring-coil c of the linedrop; but as this circuit contains no source of current the apparatus will remain inert. If the line were in use a connection would exist from battery g through the springsf andf of the spring-jack, in which a plug was inserted, to the test-ringf of spring-jack c and current would find circuit through tip 11 of plug it and relay 0. The relay being thus excited by the application of the plug to the test-ring, would open the circuit 8,inoluding the telephone,and by the breaking of the current set up by battery 'qin this circuit would produce a click in the telephone. This click in the telephone would thus signify to the operator the busy condition of the line. Finding the line to station B not in use, the operator inserts the plug h fully into the spring-jack 0 By this means the circuit from station A is continued through conductors 5 and 6 of the plug-circuit to the corresponding contact-pieces of the springjack, and thence through the conductors 10 and 11 of line to station B. At the same time one circuit is completed frombattery g through spring f tip 2' of the plug, springf and restoring-coil e of the line-drop, the current in which looks the line-drop and prevents its disturbance by subsequent signaling-currents in the line. Another circuit is completed from spring f through tip 't', conductor 7, and relay 0. The current in this circuit excites the relay, whereby the contact-points 0'0 are separated and the circuit from repeatingcoil 'm through the operators telephone is interrupted. The operator may now depress the plunger of calling-key k and transmit a signaling-current to stationB. When the subscriber at that station has responded to the call and removed his telephone from the switch-hook the circuits are in position'to permit of communication between the different sub-stations. When the conversation is terminated either subscriber may transmit a signal for disconnection by rotating his generator a whereby the clearingout annunciator 'n will be operated, its operation notifying the operator that the connection is no longer required.

It will be obvious to those skilled -in the art of telephony that other forms of mechanism might be employed to accomplish more or less indirectly the results which are attained-by the specific apparatus herein described, and I therefore do not limit myself to this particular apparatus; but

I claim as new and desire to secure by Letters Patent 1. The combination with a telephone circuit, of a plug constituting the terminal of thecircuit, a plug-seat-switch for the plug controlling the connection of an operators telephone with the circuit, a relay also controlling the connection of the telephone with the circuit, the relay being itself controlled by circuit connections closed by the insertion of the plug into a springjaclz, substantially as described.

2. The combination with a telephone circuit, of 'a plug constituting the terminal thereof, a plug-seat-switch therefor controlling the connection of an operators telephone with the circuit, arelay also controlling the connection of the telephone with the circuit, a normally open local circuit through the relay, and switch contacts adapted to be closed together to close the local circuit when the plug is inserted into a springjack, the relay being arranged to disconnect the telephone from the plug circuit when its magnet is excited, substantially as described.

3. The combination with a telephone circuit terminating in a plug, of a plug-seatswitch for the plug, a local circuit divided into two parallel branches, one of which is normally closed in the plug-seat-switch, and the other of which is open. at contact points which are adapted to be closed together by the insertion of the plug in the springjack, a relay included, with a source of current, in the local circuit, and a telephone circuit whose connection with the circuits of the plug is controlled by the relay, substantially as de scribed.

4. In combination, several pairs of connecting plugs, a plug circuit uniting the members of each pair, a repeating coil for each pair having one of its helices in the plug circuit and the other helix in circuit with an operators telephone common to all the plug circuits, a plug-seat-switch for one plug of each pair controlling the circuit of the corresponding repeating coil with the telephone, a relay also controlling said circuit, and circuit connections adapted to operate the relay to open the said circuit when the plug is inserted into a springjack, substantially as described.

In witness whereof I hereunto subscribe my namethis 8th day of November, A. D. 1894.

CHARLES E. SORIBNER.

W'itnesses:

ELLA EDLER, FRANK R. MCBERTY. 

